1. Field of the Invention
The present invention relates to game apparatuses, storage media having a game program stored therein, game systems, and game process methods, and more specifically, the invention relates to a game apparatus, a storage medium having a game program stored therein, a game system, and a game process method, in which an angular rate of an input device is used as a game input to perform a game process.
2. Description of the Background Art
Conventionally, there are game apparatuses in which an input device is moved to perform a game operation. For example, Patent Document 1 (Japanese Laid-Open Patent Publication No. 2007-75353) discloses a game system using an optical pointing device. In this game system, the input device has an image pickup means capable of picking up an image of a marker in any given position. The game apparatus acquires an image pickup result (i.e., the position of the marker or suchlike in a pickup image) by the image pickup means as operation data, and performs a game process based on the operation data. The image pickup result varies in accordance with the position and orientation of the input device, and therefore the game system allows the player to perform a game operation moving the input device itself.
The method described in Patent Document 1 uses a result of the image pickup means picking up an image of a marker for a game process, and therefore the player must use the input device such that the pickup means is directed toward the marker (the pickup means is capable of picking up an image of the marker). That is, to perform a game operation, the player always needs to direct the input device toward the marker, and therefore cannot perform the game operation with the input device being directed freely.